It is well known in the art that in the petroleum industry, certain wells that are drilled produce highly corrosive fluids or high pressure fluids that can damage the casing that is set in the well bore. The perforations in the casing in the area of the producing formations allow the corrosive production fluids to enter the casing. It is desirable in such cases, however, to introduce a packer into the casing above the perforations to seal off the upper portion of the casing from the corrosive or high pressure fluids. In such case, a production tubing string is placed within the bore-hole casing and through an opening in the packer so that the production fluids can enter the production tubing below the packer and be carried to the surface without coming in contact with the casing above the packer.
It is important in such types of wells that the fluid be treated, if it is corrosive, so it will not adversely affect the production tubing carrying the corrosive fluid to the surface. This is normally accomplished with a chemical injection valve as part of the production tubing just above the packer in the bore-hole. The treatment fluid is then pumped down the tubing/casing annulus, or through a conduit that is connected to the chemical injection valve. When sufficient pressure is applied to the chemical carrying conduit or tubing/casing annulus, the injection valve opens and the chemicals are introduced into the production tubing above the packer to treat the fluid that is going through the production tubing to the surface.
Clearly, however, this does not treat the corrosive fluid below the packer that is engaging the well bore casing, the tail pipe and the extensions coupled to and below the packer. The packer, however, allows the use of a wire-line set plug in the tail pipe for leaving the well plugged when the production tubing and seals are removed. Again, however, there is no way to treat the production fluid below the packer with the prior art system; thus the casing and pipe extension below the packer are subjected to the corrosive influence of the fluid.
If the packer is not used, the well can be treated all the way to the bottom of the casing in the area of the perforations. However, if it is desired to plug the well, it cannot be done since a packer has not been used in the well. Thus, in the prior art one can use the packer and plug off the well and treat the corrosive fluid above the packer but cannot treat the production fluid below the packer. The other option is to treat the fluid all the way to the bottom of the casing without the ability to plug off the well because there is no packer.
The present invention allows the use of a packer to plug off the well but still enables the production fluid to be treated below the packer to preserve the casing in the area of the casing perforations where the production fluid is being generated as well as the casing, the tail pipe and the pipe extensions below the packer. With the present invention, treating chemicals or water can be placed below the production packer outside the tail pipe by following passageways through the production packer so that it will wash by the perforations in the well-bore casing where the production fluids are being generated and protect the casing, the tail pipe and the packer extensions that are below the packer. It can also accommodate a wire-line set plug in the tail pipe for plugging the well and when the tubing and seals are removed, the passageways through the production packer for the chemical treatment are closed to complete the plugging of the well. In order to accomplish the present system, the production packer is used to block production fluid flow from the casing perforations below the packer in the area of the producing formations to the casing above the packer. A tubing string is placed inside the casing and coupled to and sealably extended through an opening in the blocking packer. Because the packer prevents the production fluid from rising in the casing beyond the packer, the tubing means that is coupled to and extends through the blocking packer enables production fluid to flow from the formations through the perforations in the casing and through the tubing string to the surface. The tubing string and the packer prevent the corrosive production fluids from attacking the well-bore casing above the blocking packer. A chemical injection sleeve is associated with the tubing string and the blocking packer to allow the chemical treatment fluid to flow through the blocking packer to the perforations in the casing below the packer for treatment of the production fluid which then returns to the surface through the tail pipe, packer extensions and the tubing string.
An orifice is formed in the injection sleeve below the blocking packer to allow the chemical treatment fluid to enter the well-bore casing below the blocking packer in the vicinity of the perforations to treat the production fluids. A shifting sleeve is formed concentric with the inside circumference of the injection sleeve and is movable between first and second positions. An orifice in the shifting sleeve is in alignment with the orifice in the injection sleeve in the first sleeve position such that chemical treatment fluid may flow between the tubing means and the shifting sleeve through the aligned orifices and to the production fluids being generated by the perforations in the casings. The treated fluids, as stated earlier, then are carried to the surface by the tubing string.
A shifting collar is formed on the tubing means and has a first shoulder on the shifting collar for moving the shifting sleeve to its first position aligning the injection sleeve orifice and the shifting sleeve orifice when the tubing means is first inserted in the blocking packer. A second means in the form of a second shoulder on the shifting collar moves the shifting sleeve to its second position blocking the injection sleeve orifice when the tubing sleeve is withdrawn from the blocking packer. The first and second shoulders on the shifting collar engage corresponding third and fourth shoulders on the shifting sleeve. The first shifting collar shoulder engages the third shifting sleeve shoulder when the tubing means is inserted into the injection sleeve and moves the shifting sleeve to its first position aligning the orifices in the shifting sleeve and the injection sleeve. The second shifting collar shoulder engages the fourth shifting sleeve shoulder when the tubing means is withdrawn from the blocking packer to move the shifting sleeve to its second position blocking the injection sleeve orifice. A flange is used to form the fourth shoulder on the shifting sleeve and a flange receiving groove is formed on the inner surface of the injection sleeve for receiving the flange in the second position of the shifting sleeve. This relationship creates space sufficient to enable the shifting collar to bypass the flange when the tubing means is inserted in or removed from the injection sleeve and the blocking packer. The flange is forced out of the groove when the shifting sleeve is moved to the first position by the shifting collar. First and second spaced annular sealing rings are formed on the same side of the orifice in the shifting sleeve and are in sealing contact with the injection sleeve. The first and second spaced sealing rings are located on respective sides of the orifice in the injection sleeve when the shifting sleeve is moved to the second position and thus seal the injection sleeve orifice. The seals prevent a transfer of the treated fluid to the interior of the injection sleeve when the tubing string is removed from the casing.
Thus, it is a principal object of the present invention to provide apparatus including an injection sleeve with an orifice therein for placing fluid treating chemicals or water below the production packer and outside the tail pipe to wash by the perforations generating the production fluid while at the same time accommodating a wire-line set plug in the tail pipe such that when the tubing string and its seals are removed, the orifice in the injection sleeve will close to complete the plugging of the well.
It is still a further object of the present invention to provide a shifting sleeve in the packer which moves to a first position to open an orifice in an injection sleeve when the tubing string is first inserted into the packer to allow chemical treatment of the fluid below the packer. The shifting sleeve is moved to its first position by a shifting collar on the tubing string that engages the shifting sleeve during the positioning of the tubing string in the packer. The shifting sleeve is shifted to its second position by the shifting collar to close the orifice when the tubing string is removed from the packer. When the orifice is open, the injection sleeve allows treating fluids or treating chemicals to be placed below and outside the packer. When the tail pipe is plugged and the injection sleeve orifice is closed, the well is plugged.